Dmitry Dirin

Last Name

Dirin

First Name

Dmitry

ORCID

0000-0002-5187-4555

Organisational unit

03934 - Kovalenko, Maksym / Kovalenko, Maksym

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Publications 1 - 10 of 103

Electroluminescence Generation in PbS Quantum Dot Light-Emitting Field-Effect Transistors with Solid-State Gating
Shulga, Artem G.; Kahmann, Simon; Dirin, Dmitry; et al. (2018)
ACS Nano
Ligands Mediate Anion Exchange between Colloidal Lead-Halide Perovskite Nanocrystals
Scharf, Einav; Krieg, Franziska; Elimelech, Orian; et al. (2022)
Nano Letters
The soft lattice of lead-halide perovskite nanocrystals (NCs) allows tuning their optoelectronic characteristics via anion exchange by introducing halide salts to a solution of perovskite NCs. Similarly, cross-anion exchange can occur upon mixing NCs of different perovskite halides. This process, though, is detrimental for applications requiring perovskite NCs with different halides in close proximity. We study the effects of various stabilizing surface ligands on the kinetics of the cross-anion exchange reaction, comparing zwitterionic and ionic ligands. The kinetic analysis, inspired by the "cage effect" for solution reactions, showcases a mechanism where the surface capping ligands act as anion carriers that diffuse to the NC surface, forming an encounter pair enclosed by the surrounding ligands that initiates the anion exchange process. The zwitterionic ligands considerably slow down the cross-anion exchange process, and while they do not fully inhibit it, they confer improved stability alongside enhanced solubility relevant for various applications.
Quantifying Forster Resonance Energy Transfer from Single Perovskite Quantum Dots to Organic Dyes
Feld, Leon; Boehme, Simon C.; Morad, Viktoriia; et al. (2024)
ACS Nano
Colloidal quantum dots (QDs) are promising regenerable photoredox catalysts offering broadly tunable redox potentials along with high absorption coefficients. QDs have thus far been examined for various organic transformations, water splitting, and CO2 reduction. Vast opportunities emerge from coupling QDs with other homogeneous catalysts, such as transition metal complexes or organic dyes, into hybrid nanoassemblies exploiting energy transfer (ET), leveraging a large absorption cross-section of QDs and long-lived triplet states of cocatalysts. However, a thorough understanding and further engineering of the complex operational mechanisms of hybrid nanoassemblies require simultaneously controlling the surface chemistry of the QDs and probing dynamics at sufficient spatiotemporal resolution. Here, we probe the ET from single lead halide perovskite QDs, capped by alkylphospholipid ligands, to organic dye molecules employing single-particle photoluminescence spectroscopy with single-photon resolution. We identify a Forster-type ET by spatial, temporal, and photon-photon correlations in the QD and dye emission. Discrete quenching steps in the acceptor emission reveal stochastic photobleaching events of individual organic dyes, allowing a precise quantification of the transfer efficiency, which is >70% for QD-dye complexes with strong donor-acceptor spectral overlap. Our work explores the processes occurring at the QD/molecule interface and demonstrates the feasibility of sensitizing organic photocatalysts with QDs.
Room-temperature cavity exciton-polariton condensation in perovskite quantum dots
Georgakilas, Ioannis; Tiede, David; Urbonas, Darius; et al. (2025)
Nature Communications
The exploitation of the strong light-matter coupling regime and exciton-polariton condensates has emerged as a compelling approach to introduce strong interactions and nonlinearities into numerous photonic applications. The use of colloidal semiconductor quantum dots with strong three-dimensional confinement as the active material in optical microcavities would be highly advantageous due to their versatile structural and compositional tunability and wet-chemical processability, as well as potentially enhanced, confinement-induced polaritonic interactions. Yet, to date, exciton-polariton condensation in a microcavity has neither been achieved with epitaxial nor with colloidal quantum dots. Here, we demonstrate room-temperature polariton condensation in a thin film of monodisperse, colloidal CsPbBr3 quantum dots, placed in a tunable optical resonator with a Gaussian-shaped deformation serving as wavelength-scale potential well for polaritons. The onset of polariton condensation under pulsed optical excitation is manifested in emission by its characteristic superlinear intensity dependence, reduced linewidth, blueshift, and extended temporal coherence.
Gain and lasing from CdSe/CdS nanoplatelet stripe waveguides
Belitsch, Martin; Dirin, Dmitry; Kovalenko, Maksym V.; et al. (2022)
Micro and Nano Engineering
Colloidal semiconducting nanocrystals are efficient, stable and spectrally tunable emitters, but achievable optical gain is often limited by fast nonradiative processes. These processes are strongly suppressed in slab-shaped nanocrystals (nanoplatelets), due to relaxed exciton Coulomb interaction. Here, we show that CdSe/CdS nanoplatelets can be engineered into (sub)microscopic stripe waveguides that achieve lasing without further components for feedback, i.e., just relying on the stripe end reflection. We find a remarkably high gain factor for the CdSe/CdS nanoplatelets of 1630 cm−1. In addition, by comparison with numerical simulations we assign a distinct emission peak broadening above laser threshold to emission pulse shortening. Our results illustrate the feasibility of geometrically simple monolithic microscale nanoplatelet lasers as an attractive option for a variety of photonic applications.
Non-linear Response of CdSe/CdS Quantum Dots Driven by Intense Terahertz Pulses
Gollner, Claudia; Jutas, Rokas; Dirin, Dmitry; et al. (2021)
2021 Conference on Lasers and Electro-Optics (CLEO)
We report on the observation of quantum confined stark effect (QCSE) in CdSe/CdS core/shell quantum dots (QDs) directly driven by an intense THz field, generated in the organic crystal DAST, which is pumped with multi-millijoule mid-IR pulses.
Evidence of Large Polarons in Photoemission Band Mapping of the Perovskite Semiconductor CsPbBr3
Puppin, Michele; Polishchuk, Serhii; Colonna, Nicola; et al. (2020)
Physical Review Letters
Lead-halide perovskite (LHP) semiconductors are emergent optoelectronic materials with outstanding transport properties which are not yet fully understood. We find signatures of large polaron formation in the electronic structure of the inorganic LHP CsPbBr3 by means of angle-resolved photoelectron spectroscopy. The experimental valence band dispersion shows a hole effective mass 0.26±0.02me, 50% heavier than the bare mass m0=0.17me predicted by density functional theory. Calculations of electron-phonon coupling indicate that phonon dressing of the carriers mainly occurs via distortions of the Pb-Br bond with a Fröhlich coupling parameter α=1.82. A good agreement with our experimental data is obtained within the Feynmann polaron model, validating a viable theorical method to predict the carrier effective mass of LHPs ab-initio.
Low-Cost Synthesis of Highly Luminescent Colloidal Lead Halide Perovskite Nanocrystals by Wet Ball Milling
Protesescu, Loredana; Yakunin, Sergii; Nazarenko, Olga; et al. (2018)
ACS Applied Nano Materials
Lead halide perovskites of APbX_3 type [A = Cs, formamidinium (FA), methylammonium; X = Br, I] in the form of ligand-capped colloidal nanocrystals (NCs) are widely studied as versatile photonic sources. FAPbBr_3 and CsPbBr_3 NCs have become promising as spectrally narrow green primary emitters in backlighting of liquid-crystal displays (peak at 520–530 nm, full width at half-maximum of 22–30 nm). Herein, we report that wet ball milling of bulk APbBr_3 (A = Cs, FA) mixed with solvents and capping ligands yields green luminescent colloidal NCs with a high overall reaction yield and optoelectronic quality on par with that of NCs of the same composition obtained by hot-injection method. We emphasize the superiority of oleylammonium bromide as a capping ligand used for this procedure over the standard oleic acid and oleylamine. We also show a mechanically induced anion-exchange reaction for the formation of orange-emissive CsPb(Br/I)_3 NCs.
Single-photon superabsorption in CsPbBr$_3$ perovskite quantum dots
Böhme, Simon Christian; Nguyen, Tan P.T.; Zhu, Chenglian; et al. (2025)
Nature Photonics
The absorption of light via interband optical transitions plays a key role in nature and applied technology, enabling efficient photosynthesis and photovoltaic cells, fast photodetectors or sensitive (quantum) light-matter interfaces. In many such photonic systems, enhancing the light absorption strength would be beneficial for yielding higher device efficiency and enhanced speed or sensitivity. So far, however, cavity-free light absorbers feature poorly engineerable absorption rates, consistent with the notion that the coupling strength between the initial and final states is an intrinsic material parameter. By contrast, greatly enhanced absorption rates had been theoretically predicted for superradiant systems, which feature giant oscillator strength through spatially extended coherent oscillations of the electron polarization. Unlike for emission processes, however, experimental realizations of superradiance in absorption-'superabsorption'-remain sparse and require complicated excited-state engineering approaches. Here we report superabsorption by the time reversal of single-photon superradiance in large CsPbBr3 perovskite quantum dots. Optical spectroscopy reveals a bandgap absorption that strongly increases with the quantum dot volume, consistent with a giant exciton wavefunction. Configuration-interaction calculations, quantitatively agreeing with the experiment, attribute the observed single-photon superabsorption to strong electron-hole pair-state correlations. The approach brings new opportunities for the development of more efficient optoelectronic devices and quantum light-matter interfaces.
The Lande factors of electrons and holes in lead halide perovskites: universal dependence on the band gap
Kirstein, Erik; Yakovlev, Dmitri R.; Glazov, Mikhail M.; et al. (2022)
Nature Communications
The Lande or g-factors of charge carriers are decisive for the spin-dependent phenomena in solids and provide also information about the underlying electronic band structure. We present a comprehensive set of experimental data for values and anisotropies of the electron and hole Lande factors in hybrid organic-inorganic (MAPbI(3), MAPb(Br0.5Cl0.5)(3), MAPb(Br0.05Cl0.95)(3), FAPbBr(3), FA(0.9)Cs(0.1)PbI(2.8)Br(0.2), MA=methylammonium and FA=formamidinium) and all-inorganic (CsPbBr3) lead halide perovskites, determined by pump-probe Kerr rotation and spin-flip Raman scattering in magnetic fields up to 10 T at cryogenic temperatures. Further, we use first-principles density functional theory (DFT) calculations in combination with tight-binding and k center dot p approaches to calculate microscopically the Lande factors. The results demonstrate their universal dependence on the band gap energy across the different perovskite material classes, which can be summarized in a universal semi-phenomenological expression, in good agreement with experiment.

Publications 1 - 10 of 103

Dmitry Dirin

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